Inspect landing gear box

[rudymantel]

What is the preferred way of jacking up the airplane to inspect the gear box ? Raising it by the engine mount ?
Rudy

[rudymantel]

Obviously, just to inspect the lannding gear box it is not necessary to raise the airplane. But I think it is to check the tightness of the bolts. Yes ?
The other day as I landed, (a smooth wheel landing on a paved runway)
I heard a little "klunk". So I'd like to really inspect and check the gear attachment. Would appreciate any advice on this procedure.
Rudy

[GAHorn]

Using a cradle made from 2X4's or 2X6's padded with carpet, placed between the gear-legs under the gearbox, raise the airplane so that both wheels are off the ground. Give each gearleg a vigorous "shake" to determine it's integrity. Any looseness deserves further inspection.
(See page 2-2 of the Service Manual, Series 100 Prior to 1962, Figure 2-2 for construction of a jacking block.)

[spiro]

lifting eyes.

oh yeah, I forgot, some of you don't ever go on floats or skis <g>.

if you don't have this essential hardware, this is a cool set-up:
http://home.earthlink.net/~n6d4/170b.htm
pretty sure I got the link off this forum.

- paul

[rudymantel]

Thanks guys,
Yeterday I flew my airplane to my new maintenance shop at Opa Locka airport, a 5 minute flight. (My old mechanic / AI just became an FAA inspector so he can no longer work on airplanes). They lifted the front of the plane by the engine mount, one side at a time. Shaking the left gear produced a noise like I heard- actually more of a creak than a klunck.
We found the two bolts holding the wedges in place needed tightening.
Same on the right side. No more creaking when gear shaken.

Also found just the tiniest, almost imperceptible play on the left strut-to-fuselage attachment.

I plan to change bolts on both sides at the next annual.
Rudy

[N170BP]

Now that you mention it, I'm working on '54 C-180 that we
had to pull the gear on. Those side bolts were loose on
this 180 too. Might be a good idea to check the torque on
those bolts at annual time (I think I'll check mine this weekend).

Bela P. Havasreti
'54 C-170B N170BP

[GAHorn]

(My old mechanic / AI just became an FAA inspector so he can no longer work on airplanes).

This reminded me of a time that the chief inspector of a major service center couldn't find compliance with an old AD note on a Hawker I used to manage. The AD note was issued 15 years earlier, so if not complied, the airplane will have been flying for that entire period illegally. The inspector was vehemenent that the airplane was illegal and he was going to void it's airworthiness certificate and issue citations. He and I went around for two days with him getting hotter-under-the-collar by the hour, and with me trying to assuage him into being more patient with the mechanics investigations into the alleged discrepancy.
The inspector literally shouted at me that HE had PERSONALLY researched the aircraft's records and that he was POSITIVE the airplane was illegally certificated.
Just then the chief mechanic appeared at the doorway with one of the older tattered logbooks the inspector had claimed to have thoroughly researched. He pointed out that the AD note had been complied with almost 16 years ago, earlier than the AD required by an attentive mechanic whose experience had led him to anticipate the aircraft's weakness even before the issuance of the AD note,... at this same shop,...the work having been performed by the very inspector himself,....before he was promoted to inspector!
Just proves the Peter-Principle is alive and well: By promoting this guy to inspector,...the shop in only one move had gotten rid of their best mechanic and acquired their worst inspector.

[170C]

I have a converted 172, so don't know if our gears are exactly the same at the gear boxes, but I started having trouble several years ago with my right gear getting loose. I tightened the two bolts that hold the shims in place only to have the same problem soon afterward. That time I raised all the weight off both gears & tighten both sides. It worked for some time, but just prior to annual it started again. To access the interior gear box on my Bolen conversion requires quite a bit of work to remove the plate which goes completely across the floor between the gear boxes/strut areas (no inspection holes). Means opening up the tunnel & disconnecting the rudder cable, etc. and a bunch of screws that hold the plate in place. What we eventually found was that one shim was cracked almost all the way across and the second one had started to crack. Don't know if the crack was cause by the shims getting loose & the gear moving about 1/4 " to 1" or my sometimes less than smooth landings. However after replacing the shims I have not had furthur problems & that was 3 + yrs, 300 + hours & a lot of landings, most on grass ago.

The point I want to make is to be sure you inspect those shims for cracks.